TABLE 3.

Derepression of the ytfE promoter by repressor titration

PlasmidPromoterInverted repeat sequenceaMean β-galactosidase activityb ± SD
NoneNone73 ± 5
pSTBlue-1None51 ± 1
pGIT1ytfEAAGATGCATTTAAAATACATCTT2,738 ± 426
pGIT8ytfE ΔA deletionAAGATGCATTT-AAATACATCTT80 ± 6
pGIT2hmpAAAGATGCATTTGAGATACATCAA2,832 ± 291
pGIT4ygbAAAGATGTAATATAAATACATCTT1,426 ± 329
pGIT5tehAAAAATGCATTTCAAATATACTTT1,477 ± 92
  • a Inverted repeat sequences similar to that in the ytfE promoter region are shown; underlined nucleotides match those at equivalent positions in ytfE.

  • b Cultures were grown aerobically in L broth for 16 h. β-Galactosidase activity was assayed in duplicate in three independently grown cultures. Units of activity are as defined by Miller (26).